Researchers from the University of Sydney in Australia arrived at the conclusion after reviewing the results of 10 published studies.
The review "showed very clear results that stretching is not effective in avoiding muscle soreness," says study researcher Marcos de Noronha, a PhD candidate at the university. The study is published in the latest issue of The Cochrane Database of Systemic Reviews.
Debates about what stretching can or can't do have gone on for years; advocates claim it not only reduces muscle soreness but also improves performance and reduces injury risk.
The Australian researchers focused only on the ability of stretching to reduce soreness. And if your only reason to stretch is to avoid soreness, de Noronha says the review proves "you don't need to go through the hassle because it does not actually work."
"However, if you stretch because you feel good when you do so, then go for it since there is no evidence that stretching before or after exercise is harmful," he says.
While de Noronha says this review should lay to rest the long-running debate about the effect of stretching the major muscle groups on muscle soreness, another expert tells WebMD he still believes it works and that the debate is not over yet.
A Closer Look at the Study
The Sydney researchers focused on what is known as delayed-onset muscle soreness, which usually occurs within the first day after extensive exercise and then peaks at about 48 hours. Nine of the studies were done in laboratory settings in which participants came in and exercised and then reported how sore they were later; one study looked at football players who reported their soreness after playing.
Three studies zeroed in on pre-exercise stretching, while the others assessed post-exercise stretching. Six studies compared participants assigned randomly to either stretch or not.
Participants stretched for 40 seconds to 600 seconds per session. De Noronha and researcher Robert Herbert, PhD, a senior research fellow at the university, used a 100-point scale to assess stiffness after exercise.
Pre-exercise stretching reduced soreness one day after exercise by, on average, less than 0.5 on a 100-point scale. Post-exercise stretching reduced soreness a day later by 1 point." Similar effects were evident between half a day and three days after exercise," the researchers write.
Two experts who reviewed the study results for WebMD came to different conclusions.
"It makes perfect sense," says Michael Bracko, EdD, a consulting exercise physiologist in Calgary, Alberta, and a spokesman for the American College of Sports Medicine. He has long believed that stretching does not prevent soreness. "It's a really good review, and it's information we have known for some time."
Once the pain sets in, Bracko says, stretching might reduce the soreness temporarily if you stretch then. "But the painkilling effects only last 15-20 minutes," he says.
But another expert, Pedram Aslmand, DPM, a sports podiatrist in Long Beach, Calif., doesn't think the new review will end the debate on stretching and its effect on sore muscles. "It's difficult to control for the effects of stretching on soreness," he says. For instance, some of the study participants may have had structural abnormalities -- such as shortening of the calf muscles -- that resulted in soreness despite the stretching, skewing the results.
Advice: To Stretch or Not to Stretch?
While the benefits of stretching are debated, experts say that proper, gentle stretching may not do all that exercisers hope for, but it won't hurt. Aslmand believes stretching can also help prevent injury and also can improve performance.
Bracko found, in a recent review of studies, that those who stretch regularly may get some injury protection. For many athletes, he says, stretching has become more of a ritual than anything.
So if stretching won't quell those sore muscles, what might? "Do a little light exercise," Bracko suggests.